The present invention relates to rotary valves and in particular rotary valves suitable for internal combustion engines.
It has been proposed hitherto to use rotary valves for internal combustion engines, but in order to seal the rotating valve member on the high pressure (ie compression and combustion) strokes of the engine, complex gas seals have been required. Furthermore, such systems result in high frictional loads with consequent reduction in efficiency and high wear rates. In order to reduce the problems of high frictional loads, it has been proposed to reduce the speed of rotation of the valves on the high pressure strokes of the engine, using a differential drive gear arrangement.